Heisenberg uncertainty for noob

[Bandarigoda]

Hey guys, I saw a joke about this in the jokes thread. So I went to see what it is exactly. But the thing is I didn't understand it fully. Could anyone please simplify and comprehend to me?
Also I saw that it's only for particles. What is the importance of this theory. I hope non complicated answers, cause I don't have deep knowledge in maths yet.

Thank you for your time. It's a merit for you :)

 

[jtbell]

These are very broad, vague questions. It would help if you did a little research e.g. on Wikipedia, and then come back with more specific questions. You shouldn't expect us to try to write the equivalent of a textbook chapter or Wiki page.

 

[Naty1]

edit: While I agree with jtbell, I was so mislead by Wiki [see below] and this is such
a misunderstood problem...I'll try to help.

Synopsis: Here is my own summary explanation based on half a dozen or so discussions in these forums... If you search HUP in these forums you can rummage through many pages of disagreements and clarifications. The quotes below are slightly edited posts [for brevity, clarity] from those discussions. [I had no idea what HUP really meant until arguments/discussions/and some research papers were dissected inthese forums.]

You may frequently see explanations as this one from Wikipedia under UNCERTAINTY PRINCIPLE.

In quantum mechanics, the uncertainty principle is any of a variety of mathematical inequalities asserting a fundamental limit to the precision with which certain pairs of physical properties of a particle known as complementary variables, such as position x and momentum p, can be known simultaneously.

As far as I am concerned at least very misleading [ IT may be how Heisenberg started out, but he later came, I think, to the view below.] Get a better instrument and you'll get better results.

A reasonable one line explanation: In classical mechanics we can predict with absolute precision, to arbitrary accuracy, the future position and momentum [for example] of a single particle; The HUP says no you can't!

Details:
Ques: Is it possible to simultaneously measure the position and momentum of a single particle to arbitrarily fine precision.

The HUP doesn't say anything about whether you can measure both in a single measurement at the same time. That is a separate issue.

It is possible to measure position and momentum simultaneously…a single measurement of a particle. What we can't do is to prepare an identical set of states…. such that we would be able to make an accurate prediction about what the result of a position measurement would be and an accurate prediction about what the result of a momentum measurement would be….for an ensemble of future measurements.

What we call "uncertainty" is a property of a statistical distribution. The HUP isn't about a single measurement and what can be obtained out of that single measurement. It is about how well we can predict subsequent measurements given the ‘identical’ initial conditions. The commutativity and non commutivity of operators applies to the distribution of results, not an individual measurement. This "inability to repeat identical measurement results" is in my opinion better described as an inability to prepare a state which results in identical observables.

The uncertainty principle results from uncertainties which arise when attempting to prepare a set of identically prepared states…from identical initial conditions. The wave function is not associated with an individual particle but rather with the probability for finding particles at a particular position.

 

[Naty1]

Band: So are you going to tell us the joke or what??

 

[Bandarigoda]

Joke is this, can't remember it clearly though.
Teacher ask student where is ur home work.
Student according to hup home work book is moving with x ms-1 and i don't know the position

 

[micromass]

Heisenberg is driving his car. A cop pulled him over and asked him: "Do you know how fast you were going?" He replied: "No, but I knew were I was, now I'm totally lost."

 

[micromass]

Heisenberg is driving his car. A cop pulled him over and asked him: "Do you know how fast you were going?" He replied: "No, but I knew were I was, now I'm totally lost."

The cop proceeds to check Heisenberg his car. He goes to Heisenberg and says: "Did you know that there's a dead cat in the trunk of your car?" He replied: "Well, now there is, thanks a lot"

 

[micromass]

Heisenberg was an unfortunate fellow; he knew exactly how fast his car keys were going.

 

[phinds]

Sign in the athletic dept John: "Kilroy was here !"

Sign in the physics dept John" "Heisenberg may have been here".

 

[DennisN]

The cop proceeds to check Heisenberg his car. He goes to Heisenberg and says: "Did you know that there's a dead cat in the trunk of your car?" He replied: "Well, now there is, thanks a lot"

Simply excellent.

 

[HomogenousCow]

Heisenberg was an unfortunate fellow; he knew exactly how fast his car keys were going.

That is witty, I will be stealing this joke.

I seem to always know exactly how fast my TV remote is moving.

 

[DennisN]

Hey guys, I saw a joke about this in the jokes thread. So I went to see what it is exactly. But the thing is I didn't understand it fully. Could anyone please simplify and comprehend to me?
Also I saw that it's only for particles. What is the importance of this theory. I hope non complicated answers, cause I don't have deep knowledge in maths yet.Thank you for your time. It's a merit for you :)

Bandarigoda, here is a nice clip demonstrating the uncertainty principle. (I picked it up from another PF member, I don't remember who, and I've reused it a couple of times in other threads).

https://www.youtube.com/watch?v=KT7xJ0tjB4A